I completely agree! I re-watched the season 2 Christmas special last night and season 3 episode 1 and it was so... well, happy, romantic, made sense, there was drama but there was also hope and light.
Then as season 3 progressed I started feeling that Mary was not the same anymore... I mean, she was quite mean at times and her love was showing basically through some "now kiss me" in bed. During the day she was like a different person. I also felt a bit annoyed by Matthew's lines as he seemed to be spineless at times. I realize it is very difficult to write happiness but... writers are writers for a reason, after all. And I also agree in general about the minute made resolutions of problems. Without much development of the story arc there were more than one bam-bam and all is well moments in the series. Overall, Matthew and Mary made a lot of sense in terms of relationship in the first two seasons plus some of the season 3 episodes but sometimes in season 3 they looked to me like they never had been through what they had been in the previous seasons and like their marriage was another arranged one. And it made me sad.
